1. Field of the Invention
The present invention relates to a capacitor and a method of manufacturing the same, and particularly to enhancement of capacitance density, enhancement of facultativity of electrode metal and simplification of a manufacturing process.
2. Description of the Related Art
Al electrolytic capacitors and laminated ceramic capacitors are known as capacitors which are broadly used at present. The Al electrolytic capacitors have a problem that liquid leak, etc. occurs due to use of electrolytic liquid, etc. Furthermore, the laminated ceramic capacitors require a burning step, and thus it induces thermal shrinkage between an electrode and a dielectric member, etc. For example, as a technique of implementing a compact and large-capacitance capacitor is known a grain boundary insulating type semiconductor magnetic capacitor disclosed in JP-B-Sho-61-29133, and a capacitor structure and a manufacturing method thereof disclosed in JP-A-2003-249417.
The JP-B-Sho-61-29133 discloses a grain boundary insulation type semiconductor ceramic capacitor comprising a semiconductor grain boundary insulation type dielectric ceramic having plural through holes extending to confronting end faces, external connection electrodes provided to the respective confronting end faces of the dielectric ceramic, and a capacitance electrode member which is inserted into each through hole of the dielectric ceramic and formed of metal having high melting point, the capacitance electrode members which are adjacent to each other being conductively connected to the different external connection electrodes. Furthermore, JP-A-2003-249417 discloses a method of conducting thin film formation processing using as a mask a porous substrate obtained by anodizing a substrate to form a first electrode having many columnar (pillar-shaped) members arranged regularly on the surface of a capacitor substrate, a dielectric thin film formed on the surface of the first electrode so as to cover the outside of each columnar (pillar-shaped) member, and a second electrode formed on the surface of the dielectric thin film so as to cover the outside of each columnar (pillar-shaped) member, thereby obtaining a capacitor structure.
However, the background arts as described above have the following problems.
First, in the technique of the JP-B-Sho-61-29133, the semiconductor grain boundary insulation type dielectric ceramic having plural through holes is used as the dielectric layer, and it has a structure that the capacitance electrode members are selectively inserted in the respective through holes. However, the microfabrication is difficult, and it is difficult to increase the capacitance by increasing the area. Furthermore, in the technique of the JP-A-2003-249417, adhesion of the electrode material to the porous substrate used as the mask, expansion of the holes, etc. occur owing to etching of the porous substrate itself, so that it is difficult to obtain the columnar (pillar-shaped) members having a uniform cross-sectional shape and a desired length. Furthermore, when the length of the columnar (pillar-shaped) members in the vertical direction increases, the film thickness of the dielectric thin film to be afterwards formed is liable to be dispersed, so that it is difficult to increase the capacitance by increasing the length of the columnar (pillar-shaped) members.